Gold has value because for the most of the history of mankind's use of money, Gold and Silver have repeatedly been chosen by free markets as the best form of money. Gold is durable, portable, homogeneous, fungible, divisible, rare, and recognizable.
Until 1971, most of the world's currencies were backed by Gold. In 1971, the US government defaulted on its obligation to redeem US Dollars (by which most other currencies were backed) in Gold, as agreed to by the Bretton Woods agreement of 1944. We didn't choose to go off the Gold Standard, we had no choice - Foreign Central Banks were demanding redeption in Gold, and the US didn't have enough - we inflated too much.
I think that the current swell of interest in Gold is due to the recent massive increase in the Federal Reserve's balance sheet, plus the fast growing National debt, plus a looming Social Security / Medicare crisis. People are looking for protection of their savings, and they wish to "opt-out" of the government bail-outs, government deficits, government run health-care, and government money printing. They are looking for a currency that doesn't have a counter-party.
"Gold is money and nothing else" - JP Morgan
"In the absence of the gold standard, there is no way to protect savings from confiscation through inflation. There is no safe store of value. If there were, the government would have to make its holding illegal, as was done in the case of gold. If everyone decided, for example, to convert all his bank deposits to silver or copper or any other good, and thereafter declined to accept checks as payment for goods, bank deposits would lose their purchasing power and government-created bank credit would be worthless as a claim on goods. The financial policy of the welfare state requires that there be no way for the owners of wealth to protect themselves.
This is the shabby secret of the welfare statists' tirades against gold. Deficit spending is simply a scheme for the confiscation of wealth. Gold stands in the way of this insidious process. It stands as a protector of property rights. If one grasps this, one has no difficulty in understanding the statists' antagonism toward the gold standard." - Alan Greenspan